阅读说明：本技术 带电粒子束照射装置 (Charged particle beam irradiation apparatus ) 是由 古川卓司 原洋介 于 2021-03-24 设计创作，主要内容包括：本发明提供带电粒子束照射装置。在以往的带电粒子束照射装置中,存在因用于对照射口供电的电缆引起的问题。带电粒子束照射装置具备：聚束电磁铁,通过使带电粒子束偏转,连续改变带电粒子束向等角点的照射角；照射口,沿着聚束电磁铁的有效磁场区域的射出侧的形状连续移动,从聚束电磁铁射出的带电粒子束经过照射口向等角点照射；供电导轨,以沿着有效磁场区域的射出侧的形状的方式设置；集电靴,经由支撑部件固定于照射口,沿着供电导轨滑动,将来自供电导轨的电力供给到照射口,所述集电靴的与供电导轨接触的面具有与供电导轨相同的弯曲半径或供电导轨的平均弯曲半径且/或所述集电靴与供电导轨的平坦的侧面接触并且沿着供电导轨滑动。(The invention provides a charged particle beam irradiation apparatus. In the conventional charged particle beam irradiation apparatus, there is a problem caused by a cable for supplying power to the irradiation port. A charged particle beam irradiation device is provided with: a beam-focusing electromagnet for continuously changing an irradiation angle of the charged particle beam to the isocenter by deflecting the charged particle beam; an irradiation port that continuously moves along the shape of the emission side of the effective magnetic field region of the bunching electromagnet, and through which the charged particle beam emitted from the bunching electromagnet is irradiated toward the isocenter; a power supply rail provided so as to follow the shape of the emission side of the effective magnetic field region; and a collector shoe fixed to the irradiation port via a support member and sliding along the power supply rail to supply the power from the power supply rail to the irradiation port, wherein a surface of the collector shoe, which is in contact with the power supply rail, has the same bending radius as the power supply rail or an average bending radius of the power supply rail, and/or the collector shoe, which is in contact with a flat side surface of the power supply rail and slides along the power supply rail.)

1. A charged particle beam irradiation apparatus is provided with:

a beam-focusing electromagnet for deflecting the charged particle beam to continuously change an irradiation angle of the charged particle beam to the isocenter;

an irradiation port that continuously moves along a shape of an emission side of an effective magnetic field region of the bunching electromagnet, and through which the charged particle beam emitted from the bunching electromagnet passes to irradiate the isocenter;

a power supply rail provided so as to follow the shape of the emission side of the effective magnetic field region; and

a collector shoe fixed to the irradiation port via a support member, the collector shoe sliding along the power supply rail and supplying power from the power supply rail to the irradiation port,

the surface of the collector shoe that is in contact with the power supply rail has the same bending radius as the power supply rail or the average bending radius of the power supply rail, and/or

The collector shoe is in contact with the flat side of the power supply rail and slides along the power supply rail.

2. The charged particle beam irradiation apparatus according to claim 1,

the bunching electromagnet, the power supply guide rail and the collector shoe are arranged in an end mask, and all or part of the irradiation port is positioned outside the end mask.

3. A charged particle beam irradiation apparatus is provided with:

a beam-focusing electromagnet for deflecting the charged particle beam to continuously change an irradiation angle of the charged particle beam to the isocenter;

an irradiation port that continuously moves along a shape of an emission side of an effective magnetic field region of the bunching electromagnet, and through which the charged particle beam emitted from the bunching electromagnet passes to irradiate the isocenter;

a power supply rail provided so as to follow the shape of the emission side of the effective magnetic field region; and

a collector shoe fixed to the irradiation port via a support member, the collector shoe sliding along the power supply rail and supplying power from the power supply rail to the irradiation port,

the collector shoe is composed of a plurality of collector parts,

the surfaces of the current collecting portions, which are in contact with the power supply rail, have the same radius of curvature as the power supply rail or the average radius of curvature of the power supply rail.

4. The charged particle beam irradiation apparatus according to any one of claims 1 to 3,

the structure is such that a biasing means is provided between the support member and the collector shoe, and a constant load is applied to the collector shoe by the biasing means.

5. The charged particle beam irradiation apparatus according to any one of claims 1 to 4, further comprising:

a drive rail provided so as to follow the shape of the emission side of the effective magnetic field region; and

a drive unit fixed to the irradiation port via the support member and configured to be continuously movable along the drive rail while the irradiation port is supported by the drive rail,

the power is supplied from the power supply rail to the drive unit via the collector shoe.

6. The charged particle beam irradiation apparatus according to any one of claims 1 to 5,

the bunching electromagnet has a pair of coils arranged so as to sandwich a path of the charged particle beam,

the coil pair is configured to generate an effective magnetic field region in which a magnetic field is directed toward a Z axis, which is a direction orthogonal to an X axis, which is a traveling direction of the charged particle beam, when a current is input, wherein an axis orthogonal to both the X axis and the Z axis is a Y axis,

on the surface of the X and Y plane,

a charged particle beam deflected at a deflection starting point Q at a deflection angle phi with respect to an X-axis and incident on the effective magnetic field region is deflected by the effective magnetic field region to irradiate the isocenter through the irradiation port at an irradiation angle theta with respect to the X-axis,

an arbitrary point P2 on the boundary of the effective magnetic field region on the charged particle beam emission side is located at an equal distance r from the isocenter₁In the position of (a) in the first,

the point P1 and the point P2 on the boundary of the effective magnetic field region on the incident side of the charged particle beam are located at the radius r₂And the arc of the central angle (theta + phi),

if the distance between the deflection starting point Q and the isocenter is L, the distance R between the deflection starting point Q and the point P1 satisfies the relational expression (4):

[ mathematical formula 1 ]

7. The charged particle beam irradiation apparatus according to claim 6,

the bunching electromagnet is provided with a 1 st coil pair and a 2 nd coil pair,

the 1 st coil pair and the 2 nd coil pair are arranged so as to be aligned in the Y-axis direction with the path of the charged particle beam therebetween,

the 1 st coil pair and the 2 nd coil pair are configured such that magnetic fields of the generated effective magnetic field regions are oriented opposite to each other.

8. The charged particle beam irradiation apparatus according to claim 6 or 7, further comprising:

and a deflection electromagnet that deflects the charged particle beam from the accelerator that generates the charged particle beam at the deflection starting point Q by a deflection angle Φ of 10 degrees or more.

Technical Field

The present invention relates to a charged particle beam irradiation apparatus.

Background

Particle beam therapy has been conventionally performed for treating malignant tumors such as cancer by irradiating the malignant tumors with charged particle beams accelerated to high energy.

In particle beam therapy, a scanning irradiation method is performed in which a fine charged particle beam extracted from an accelerator is scanned in a lateral direction by a scanning electromagnet, and a lesion is divided into layers in a particle beam traveling direction, thereby enabling three-dimensional irradiation. In order to transport a charged particle beam extracted from an accelerator for charged particles to an irradiation target in a treatment room, a beam transport system including a deflection electromagnet, a beam focusing electromagnet, or the like is used, and the beam transport system includes an irradiation port (nozzle) having a scanning electromagnet or an energy modulation unit at an end on the irradiation target side.

In the particle beam irradiation apparatus described in patent document 1, an irradiation angle can be continuously selected for an irradiation target, and a rotating gantry for rotating a large irradiation apparatus is required (patent document 1). In this case, a large current needs to be supplied to a device such as an electromagnet or an irradiation device used for particle beam therapy, and a power cable such as a CV cable (crosslinked polyethylene insulated ethylene sheathed cable) that allows a large current is used. Such a cable is made relatively thick, and the bending radius (curvature) of the thick cable becomes large. When several tens to several hundreds of these thick cables are bundled for use, there is a problem that the storage space for the cables must be enlarged. Further, the rotating gantry is rotated by about 180 degrees at maximum in the clockwise direction and the counterclockwise direction, but it is necessary to rotate the cables in cooperation with each other, and there is a problem that the cables are wound or worn due to the rotation.

Patent document 2 discloses a charged particle beam irradiation apparatus that irradiates a target with a charged particle beam from an arbitrary angle without using a rotating gantry.

In a conventional charged particle beam irradiation apparatus, when an irradiation port to which a large current is supplied moves, a flexible cable (cable) or the like that can move while being kept energized is generally used as shown in fig. 10. However, since the cable such as a hose cable is covered with a very thick portion, the bending radius is increased, which causes a problem that the entire apparatus is bulky. In addition, when such large and thick cables are positioned to enter the visual field of the patient and the patient under treatment sees the cable movement, psychological stress or anxiety may be applied to the patient.

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese Kohyo publication (Kokai) No. 2013-505757

Patent document 2: japanese patent No. 6387476

Disclosure of Invention

Problems to be solved by the invention

In view of the above, an object of the present invention is to provide a charged particle beam irradiation apparatus configured to supply power from a power supply rail to an irradiation port without using a relatively thick power supply cable for operating the irradiation port.

Means for solving the problems

The present invention includes the following modes [ 1 ] to [ 8 ].

〔1〕

A charged particle beam irradiation apparatus is provided with:

a beam-focusing electromagnet for deflecting the charged particle beam to continuously change an irradiation angle of the charged particle beam to the isocenter;

an irradiation port that continuously moves along a shape of an emission side of an effective magnetic field region of the bunching electromagnet, and through which the charged particle beam emitted from the bunching electromagnet passes to irradiate the isocenter;

a power supply rail provided so as to follow the shape of the emission side of the effective magnetic field region; and

a collector shoe fixed to the irradiation port via a support member, sliding along the power supply rail, and supplying power from the power supply rail to the irradiation port,

the surface of the collector shoe that is in contact with the power supply rail has the same bending radius as the power supply rail or the average bending radius of the power supply rail, and/or

The collector shoe is in contact with the flat side of the power supply rail and slides along the power supply rail.

〔2〕

The charged particle beam irradiation apparatus described in [ 1 ], wherein,

the bunching electromagnet, the power supply guide rail and the collector shoe are arranged in the end mask, and all or part of the irradiation opening is positioned outside the end mask.

〔3〕

A charged particle beam irradiation apparatus is provided with:

a beam-focusing electromagnet for deflecting the charged particle beam to continuously change an irradiation angle of the charged particle beam to the isocenter;

an irradiation port that continuously moves along a shape of an emission side of an effective magnetic field region of the bunching electromagnet, and through which the charged particle beam emitted from the bunching electromagnet passes to irradiate the isocenter;

a power supply rail provided so as to follow the shape of the emission side of the effective magnetic field region; and

a collector shoe fixed to the irradiation port via a support member, the collector shoe sliding along the power supply rail and supplying power from the power supply rail to the irradiation port,

the collector shoe is composed of a plurality of collector parts,

the surfaces of the current collecting portions, which are in contact with the power supply rail, have the same radius of curvature as the power supply rail or the average radius of curvature of the power supply rail.

〔4〕

The charged particle beam irradiation apparatus as described in [ 1 ] to [ 3 ], wherein,

the structure is such that a biasing means is provided between the support member and the collector shoe, and a constant load is applied to the collector shoe by the biasing means.

〔5〕

The charged particle beam irradiation apparatus according to any one of [ 1 ] to [ 4 ], further comprising:

a drive rail provided so as to follow the shape of the emission side of the effective magnetic field region; and

a drive section fixed to the irradiation port via the support member, the irradiation port being supported by the drive rail and continuously moving along the drive rail,

the power is supplied from the power supply rail to the drive unit via the collector shoe.

〔6〕

The charged particle beam irradiation apparatus according to any one of [ 1 ] to [ 5 ], wherein,

the bunching electromagnet has a pair of coils arranged so as to sandwich a path of the charged particle beam,

the coil pair is configured to generate an effective magnetic field region in which a magnetic field is directed toward a Z axis, which is a direction orthogonal to an X axis, which is a traveling direction of the charged particle beam, when a current is input, wherein an axis orthogonal to both the X axis and the Z axis is a Y axis,

on the surface of the X and Y plane,

a charged particle beam deflected at a deflection starting point Q at a deflection angle phi with respect to an X-axis and incident on the effective magnetic field region is deflected by the effective magnetic field region to irradiate toward the isocenter through the irradiation port at an irradiation angle theta with respect to the X-axis,

an arbitrary point P2 on the boundary of the effective magnetic field region on the charged particle beam emission side is located at an equal distance r from the isocenter₁In the position of (a) in the first,

the point P1 and the point P2 on the boundary of the effective magnetic field region on the incident side of the charged particle beam are located at the radius r₂And the arc of the central angle (theta + phi),

if the distance between the deflection starting point Q and the isocenter is L, the distance R between the deflection starting point Q and the point P1 satisfies the relational expression (4):

[ mathematical formula 1 ]

〔7〕

The charged particle beam irradiation apparatus described in [ 6 ], wherein,

the bunching electromagnet is provided with a 1 st coil pair and a 2 nd coil pair,

the 1 st coil pair and the 2 nd coil pair are arranged so as to be aligned in the Y-axis direction with the path of the charged particle beam therebetween,

the 1 st coil pair and the 2 nd coil pair are configured such that magnetic fields of the generated effective magnetic field regions are oriented opposite to each other.

〔8〕

The charged particle beam irradiation apparatus according to any one of [ 6 ] and [ 7 ], further comprising:

and a deflection electromagnet that deflects the charged particle beam from the accelerator that generates the charged particle beam at the deflection starting point Q by a deflection angle Φ of 10 degrees or more.

Effects of the invention

In the charged particle beam irradiation apparatus according to the embodiment of the present invention, since the electric power is supplied from the power supply rail to the irradiation port without using a relatively thick power supply cable for operating the irradiation port, it is possible to solve or reduce a problem of a storage space for a thick cable having a large bending radius, a problem of damage to the cable due to handling of the cable, and the like.

Drawings

Fig. 1 is a schematic configuration diagram of a charged particle beam irradiation apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic configuration diagram of a bunching electromagnet.

Fig. 3 is a diagram for explaining formation of an effective magnetic field region.

Fig. 4 is a schematic configuration diagram of a charged particle beam irradiation apparatus.

Fig. 5 is a front view and a side view of the charged particle beam irradiation apparatus on the irradiation port side.

FIG. 6 is a sectional view schematically showing the configuration of the irradiation port and the power supply system.

Fig. 7 is a diagram for explaining the shape of the contact surface of the collector shoe.

Fig. 8 is a view for explaining the shapes of a plurality of collector portions of a collector shoe.

Fig. 9 is a block diagram of a control system of the charged particle beam irradiation apparatus.

Fig. 10 is a diagram for explaining a conventional charged particle beam irradiation apparatus.

Description of the reference symbols

10 charged particle beam irradiation apparatus

20 accelerator

30 charged particle beam delivery system

31 charged particle beam adjusting unit

32 vacuum pipeline

33 deflection electromagnet

34 fan-shaped vacuum pipeline

40 bunching electromagnet

41(41a, 41b) effective magnetic field region

42 incident side

43 injection side

44 (44a, 44b) coil

45 magnetic pole

46 magnetic yoke

48 port cover

100 irradiation port

101 scanning electromagnet

102 wave beam monitor

103 energy modulation unit

120 power supply system

121 supporting member

122 drive part

123 collector shoe

124 drive rail

125 power supply guide rail

126 insulating member

140 control system

141 irradiation control unit

142 electromagnet control unit

143 scan control unit

144 irradiation port drive control unit

145 power supply control section.

Detailed Description

One embodiment of the present invention relates to a charged particle beam irradiation apparatus 10, which includes an irradiation port that continuously moves along a shape of an emission side of an effective magnetic field region of a bunching electromagnet and irradiates an isocenter (iso center) with a charged particle beam (also referred to as a particle beam), and a power supply system that supplies electric power to the irradiation port.

< charged particle Beam irradiation apparatus 10>

Fig. 1 is a schematic configuration diagram of a charged particle beam irradiation apparatus 10 according to an embodiment of the present invention. The charged particle beam irradiation apparatus 10 includes a beam focusing electromagnet 40 and an irradiation port 100. The charged particle beam irradiation apparatus 10 may further include an accelerator 20 and a charged particle beam transport system 30. The irradiation port 100 is disposed in a treatment room provided with a treatment table on which a patient is placed.

The bunching electromagnet 40 is built in the vacuum vessel, and the effective magnetic field area of the bunching electromagnet 40 through which the charged particle beam passes is kept vacuum. The vacuum vessel (and a drive rail and a power supply rail described later) of the bunching electromagnet 40 is built in the port cover 48, and the bunching electromagnet 40 and the power supply system 120 described later cannot be seen from the patient or medical staff when the charged particle beam irradiation apparatus 10 is used. This reduces psychological stress and burden on the patient during particle beam therapy, and prevents an accident such as an electric shock due to contact with the power supply rail, which will be described later, thereby ensuring safety. The irradiation port 100, which will be described later, is located entirely or partially outside the end mask 48 and is visible from the patient during the particle beam therapy.

The accelerator 20 is a device that generates a charged particle beam, and is, for example, a synchrotron, a cyclotron, or a linear accelerator. The charged particle beam generated by the accelerator 20 is introduced to the bunching electromagnet 40 via the charged particle beam transport system 30.

The charged particle beam transport system 30 includes one or more charged particle beam adjustment units 31, a vacuum duct 32, a deflection electromagnet 33, a fan-shaped vacuum duct 34, and the like. The accelerator 20, the charged particle beam adjusting unit 31, and the deflection electromagnet 33 are connected by a vacuum duct 32, and the deflection electromagnet 33 and the bunching electromagnet 40 are connected by a fan-shaped vacuum duct 34. By forming the fan-shaped vacuum duct 34 of the XY plane (see fig. 2) into a fan shape, even a charged particle beam deflected at a deflection angle Φ of 10 degrees or more can pass through the vacuum duct, and the vacuum duct can be made smaller than a rectangular vacuum duct, and the installation space can be reduced.

The charged particle beam is generated by the accelerator 20 on the upstream side, travels through the vacuum ducts 32 and 34 to avoid or reduce attenuation, is adjusted by the charged particle beam adjusting means 31, and is introduced into the bunching electromagnet 40 on the downstream side.

The charged particle beam adjusting means 31 appropriately includes, according to the specifications: a Beam slit (Beam slit) for adjusting the Beam shape and/or dose of the charged particle Beam; an electromagnet for adjusting a traveling direction of the charged particle beam; a quadrupole electromagnet for adjusting a beam shape of the charged particle beam; and a steering electromagnet or the like for fine-tuning the beam position of the charged particle beam.

The path from the deflection electromagnet 33 of the charged particle beam to the isocenter O (affected part of the patient) differs depending on an irradiation angle θ described later. Therefore, the optical factor received by the charged particle beam also changes according to the irradiation angle θ, and the beam shape of the charged particle beam at the isocenter O may change according to the irradiation angle θ. In contrast, for example, the charged particle beam adjusting means 31 provided upstream of the bunching electromagnet 40 may be controlled for each irradiation angle θ, and the beam shape of the charged particle beam at the isocenter O may be adjusted to be appropriate.

The deflection electromagnet 33 is configured to continuously deflect the charged particle beam at a deflection angle Φ to be described later and emit the charged particle beam to the bunching electromagnet 40. The bunching electromagnet 40 is configured to continuously change the irradiation angle θ of the charged particle beam toward the isocenter O. Here, the contents of prior patents (japanese patent No. 6364141, japanese patent No. 6387476) of the same applicant as the present application are incorporated by reference into the present specification, and examples of the deflecting electromagnet 33 and the bunching electromagnet 40 are briefly described below.

Fig. 2 (a) is a schematic configuration diagram of the bunching electromagnet 40. In fig. 2, the traveling direction of the charged particle beam is defined as an X axis, the direction of the magnetic field generated by the bunching electromagnet 40 is defined as a Z axis, and the direction orthogonal to the X axis and the Z axis is defined as a Y axis. The bunching electromagnet 40 is configured to bunch a charged particle beam incident from a range having a large deflection angle Φ with respect to the X axis at the isocenter O on the XY plane. In fig. 2 to 3, the irradiation port 100 is omitted, and for the sake of simplicity of explanation, the isocenter O is set as the origin in the XYZ space, and the upstream side (accelerator side) is set as the positive direction of the X axis.

The deflection angle phi may range from greater than-90 degrees to less than +90 degrees, and the range of the positive (+ Y-axis direction) deflection angle and the range of the negative (-Y-axis direction) deflection angle may also be different (asymmetric). For example, the maximum deflection angle (Φ ═ Φ max) on the positive side may be any one of 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 85 degrees, and the maximum deflection angle (Φ ═ Φ max) on the negative side may be any one of-10 degrees, -15 degrees, -20 degrees, -25 degrees, -30 degrees, -35 degrees, -40 degrees, -45 degrees, -50 degrees, -60 degrees, -70 degrees, -80 degrees, and-85 degrees.

The bunching electromagnet 40 includes 1 or more coil pairs that generate uniform magnetic fields (effective magnetic field regions 41a and 41b) oriented in a direction (Z-axis direction in the drawing) orthogonal to the traveling direction of the charged particle beam and the expansion direction of the deflection angle Φ of the charged particle beam, and are arranged with the charged particle beam path therebetween. The effective magnetic field area generated by the 1 coil pair of the bunching electromagnet 40 has a crescent shape in the XY plane as shown in (a) of fig. 2, which is described in detail later. In addition, since the gap (distance in the Z-axis direction) between the opposed coil pairs through which the charged particle beam passes is sufficiently smaller than the range in which the charged particle beam spreads in the XY plane, the spread in the Z-axis direction of the charged particle beam is not considered here.

Fig. 2 (b) is a cross-sectional view taken along line a-a of the bunching electromagnet 40. The bunching electromagnet 40 preferably has at least two sets of coil pairs 44a, 44 b. Magnetic poles (poles) 45a and 45b are respectively incorporated in the coils 44a and 44b, and yokes 46 are connected to the magnetic poles 45a and 45 b. The bunching electromagnet 40 is connected to a power supply device (electromagnet control unit 142 described later), and the bunching electromagnet 40 is excited by supplying a current (excitation current) from the power supply device to the coil pairs 44a and 44b, thereby forming effective magnetic field regions 41a and 41b (also collectively referred to as effective magnetic field regions 41). ).

The range of the effective magnetic field region 41a and the range of the effective magnetic field region 41b may be different (asymmetric). For example, if the range of the positive (+ Y-axis direction) deflection angle Φ and the range of the negative (-Y-axis direction) deflection angle Φ are asymmetric, the effective magnetic field regions 41a and 41b are also asymmetrically formed, and thus the unused effective magnetic field regions can be reduced, and the manufacturing cost and power consumption can be reduced.

The deflection angle Φ of the charged particle beam deflected by the deflection electromagnet 33 and incident on the bunching electromagnet 40 ranges from a positive maximum deflection angle (Φ ═ Φ max) to a negative maximum deflection angle (Φ ═ Φ max), the positive maximum deflection angle Φ max is an angle of 10 degrees or more and less than 90 degrees, and the negative maximum deflection angle- Φ max is an angle of more than-90 degrees and less than-10 degrees. The deflection angle Φ and an irradiation angle θ described later are angles of the path of the charged particle beam with respect to the X axis in the XY plane.

The charged particle beam incident in the positive deflection angle range (phi > 0 to phi max) is deflected by the effective magnetic field region 41a of the 1 st coil pair 44a, passes through the irradiation port 100, and is irradiated to the isocenter O. The charged particle beam incident in the negative deflection angle range (phi is less than 0 to-phi max) is deflected by the effective magnetic field region 41b of the 2 nd coil pair 44b, passes through the irradiation port 100, and is irradiated to the isocenter O. The directions of the magnetic fields of the effective magnetic field region 41a and the effective magnetic field region 41b are opposite to each other. The charged particle beam incident on the bunching electromagnet 40 from the deflection electromagnet 33 at a deflection angle Φ equal to 0 passes through one of the effective magnetic field regions 41a and 41b or between the two regions 41a and 41b, and is bunched at the isocenter O through the irradiation port 100.

The deflection angle phi of the charged particle beam incident on the bunching electromagnet 40 is controlled by the deflection electromagnet 33. The deflection electromagnet 33 generates a magnetic field in a direction (Z axis in the figure) orthogonal to the traveling direction (X axis in the figure) of the charged particle beam supplied from an accelerator (not shown), and includes an electromagnet for deflecting the passing charged particle beam, and a control unit (not shown) for controlling the intensity and direction of the magnetic field. The deflection electromagnet 33 deflects the charged particle beam on the XY plane by controlling the magnetic field strength and the direction (Z axis direction) of the deflection electromagnet 33 by an electromagnet control unit 142 described later, and causes the charged particle beam deflected at the deflection starting point Q at the deflection angle Φ to be emitted to the convergence electromagnet 40. Here, the deflection start point Q and the isocenter O are located on the X axis.

With reference to fig. 3, a calculation formula for forming the effective magnetic field region 41a of the bunching electromagnet 40 will be described. In this embodiment, the formation of the effective magnetic field region in the XY plane will be described without considering the deflection of the charged particle beam in the Z axis direction. The effective magnetic field region 41a of the bunching electromagnet 40 is described, but the same applies to the effective magnetic field region 41b, and the description is omitted.

First, the boundary of the effective magnetic field region 41a on the charged particle beam emission side 43 of the focusing electromagnet 40 is determined to be located at an equal distance r from the isocenter O₁A range of positions of (a). Next, the boundary of the effective magnetic field region 41a on the charged particle beam incident side 42 of the bunching electromagnet 40 is determined as follows: based on relational expressions (1) to (5) described later, the incident charged particle beam is converged at the isocenter O by deflecting the virtual deflection starting point Q located at a predetermined distance L from the isocenter O at a deflection angle Φ. Here, the virtual yaw starting point Q is: it is assumed that at the center of the deflection electromagnet 33, the charged particle beam is subjected to a kick (kick) point of the deflection angle phi over a very short distance.

The charged particle beam transported at the deflection angle Φ enters from an arbitrary (arbitrary) point P1 on the boundary of the effective magnetic field region 41a on the incident side 42, and performs a circular motion with a curvature radius r2 in the effective magnetic field region 41a (the central angle in this case is (Φ + θ)). ) The light is emitted from a point P2 on the boundary of the effective magnetic field region 41a on the emission side 43 toward the isocenter O. That is, points P1 and P2 are located at radius r₂And the arc of the central angle (phi + theta).

On the XY plane, an XY coordinate system with the isocenter O as the origin is assumed. When the irradiation angle θ is defined as an angle formed by the X axis and a straight line connecting the point P2 on the exit side 43 and the isocenter O, the coordinates (X, y) of the point P1 on the entrance side 42, the deflection angle Φ, and the distance R between the point Q and the point P1 are obtained by the following relational expressions (1) to (4).

[ mathematical formula 2 ]

x＝r₁cosθ+r₂(sinθ+sinΦ) (1)

y＝r₁sinθ-r₂(cosθ-cosΦ) (2)

Here, when a magnetic field of uniform magnetic flux density B is generated in the effective magnetic field region 41a, and the movement amount of the charged particle beam is p (mainly determined by the accelerator) and the electric charge is q, the curvature radius r of the charged particle beam deflected in the magnetic field is₂Represented by formula (5).

[ mathematical formula 3 ]

By adjusting the shape and arrangement of the coil pair 44a and the magnetic pole 45a of the bunching electromagnet 40 and adjusting the current flowing through the coil pair 44a according to the relational expressions (1) to (5), the shape of the boundary of the effective magnetic field region 41a can be adjusted. That is, the boundary is determined such that the distance between an arbitrary point P2 on the boundary of the effective magnetic field region 41a on the emission side 43 and the isocenter O becomes equal distance r₁The magnetic flux density B of the effective magnetic field region 41a is adjusted, and r is determined according to the equation (5)₂And the boundary of effective magnetic field area 41a on incident side 42 is determined in such a manner that distance R between point P1 on the boundary of effective magnetic field area 41a on incident side 42 and deflection starting point Q has the relationship of expression (4). The maximum value of phi in equation (3) becomes the maximum deflection angle phi max. In a preferred embodiment, which is not intended to be limiting, the deflection start point Q is adjusted so that the charged particle beam passing through the deflection start point Q is focused at the isocenter O without being deflected by the focusing electromagnet 40The arrangement of the point Q, the bunching electromagnet 40, and the isocenter O makes the device structure simpler.

The boundaries of the effective magnetic field regions 41a and 41b of the bunching electromagnet 40 determined in the above manner are ideal shapes for bunching the charged particle beam at the isocenter O. In fact, even if there is a deviation from the ideal shape or a non-uniformity in the magnetic field distribution, the amount of excitation (magnetic flux density B) of the bunching electromagnet 40 is finely adjusted for each deflection angle Φ, the information is stored in the power supply device (for example, the irradiation control unit 121), and the deflection angle Φ and the current amount of the bunching electromagnet 40 are controlled in conjunction with each other, whereby the charged particle beam can be deflected so as to conform to the isocenter O. In addition, even when the nonuniformity of the magnetic field distribution can be predicted in advance, the trajectory of the charged particle beam can be finely adjusted by correcting the shapes and the arrangements of the pair of coils 44a, 44b and the magnetic poles 45a, 45b of the bunching electromagnet 40.

< irradiation opening 100>

The irradiation port 100 of the charged particle beam irradiation apparatus 10 will be described.

Fig. 4 is an enlarged schematic view of the effective magnetic field regions 41(41a, 41b) of the deflection electromagnet 33, the fan-shaped vacuum duct 34, the bunching electromagnet 40, and the irradiation port 100, which are downstream of the charged particle beam irradiation device 10.

The irradiation port 100 is located in a treatment room where treatment using a charged particle beam or the like is performed, and continuously moves on the XY plane so as to follow the shape (boundary shape) of the emission side 43 of the effective magnetic field region 41. The charged particle beam directed from the emission side 43 of the effective magnetic field region 41 toward the isocenter O passes through the irradiation port 100, and the traveling direction of the charged particle beam and the like are finely adjusted by the irradiation port 100.

The irradiation port 100 includes a scanning electromagnet 101, a beam monitor 102, and an energy modulation unit 103. The scanning electromagnet 101 can finely adjust the traveling direction of the charged particle beam emitted from the irradiation port 100 by adjusting the amount of current flowing and the direction of current flow, and can scan (scan) the charged particle beam in a relatively narrow range. The beam monitor 102 monitors the charged particle beam, and measures the position and flatness of the dose monitor or beam. The energy modulation unit 103 adjusts the energy of the charged particle beam to adjust the depth to which the charged particle beam reaches inside the patient. The energy modulation unit 103 is, for example, a range adjuster, a diffuser, a ridge filter, a patient collimator, a patient injector (bolus), an applicator, or a combination thereof.

< Power supply System 120>

The power supply system 120 of the irradiation port 100 will be described with reference to fig. 5 to 9.

Fig. 5 (a) is a front view of the charged particle beam irradiation device 10 as viewed from the patient side, and fig. 5 (b) is a side view thereof. Fig. 6 is a schematic cross-sectional view of the power supply system 120, the irradiation port 100, and the end mask 48, as viewed from above.

The power supply system 120 includes: a driving unit 122 and a collector shoe 123 provided on a support member 121 fixed to the irradiation port 100; a drive rail 124 for moving the irradiation port 100 along the shape of the emission side 43 of the effective magnetic field region 41 of the beam focusing electromagnet 40; and a power supply rail 125 for supplying power to the irradiation port 100 and the driving unit 122 via the collector shoe 123.

In order to prevent short-circuiting or leakage, the power supply rail 125 is fixed inside the end cover 48 via an insulating member 126. The number of the drive rail 124 and the power supply rail 125 is not limited to the number shown in the figure, and may be 1 or more.

In the power supply system 120, the drive rail 124 and the power supply rail 125 are provided in the port cover 48 of the vacuum vessel incorporating the bunching electromagnet 40 so as to follow the shape of the emission side 43 of the effective magnetic field region 41 of the bunching electromagnet 40 on the XY plane. Here, "so as to follow the shape of the exit side 43 of the effective magnetic field region 41" may mean that the charged particle beam directed from the exit side 43 of the effective magnetic field region 41 toward the isocenter O can pass through the irradiation port 100 at any irradiation angle θ used in the charged particle beam irradiation apparatus 10, but the drive rail 124 and the power feed rail 125 are preferably formed to have the same or similar shape as the exit side 43 of the effective magnetic field region 41 on the XY plane. By forming the power feeding rail 125 on the XY plane in the same or similar shape as the shape of the emission side 43 of the effective magnetic field region 41, it is possible to suppress a change in contact resistance between the collector shoe 123 and the power feeding rail 125 regardless of the position of the emission port 100 in the driving range, and to obtain stable power supply, which is preferable in this respect.

Fig. 6 (a) shows a mode in which the power supply rail 125 is positioned inside the drive rail 124, and fig. 6 (b) shows a mode in which the drive rail 124 is positioned inside the power supply rail 125. In the present invention, although any aspect may be adopted, in the aspect shown in fig. 6 (b), since the relatively heavy irradiation port 100 is located in the vicinity of the driving unit 122, the influence of the moment applied to the support member 121 accompanying the movement of the irradiation port 100 can be reduced.

In fig. 6, the cross section of the feeding rail 125 on the XZ plane is flat, but may be curved toward the collector shoe 123 to improve the contact with the collector shoe 123. As shown in fig. 6 (c), the collector shoe 123 may be configured to sandwich a flat side surface of the power supply rail 125. With this configuration, the contact between the flat surface of the collector shoe 123 and the side surface of the flat power supply rail 125 can be maintained high, and the collector shoe 123 can slide (be folded) along the power supply rail 125.

The driving unit 122 includes a driving motor and a driving mechanism, which are fixed to the irradiation port 100 via the support member 121, and the irradiation port 100 is supported by the driving rail 124 and continuously moves (moves while being supported) along the driving rail 124.

The charged particle beam emitted from the emission side 43 of the effective magnetic field region 41 of the bunching electromagnet 40 travels in a straight line. Therefore, the irradiation port 100 can be configured such that attenuation of the charged particle beam is suppressed to the maximum by the charged particle beam coming out of the effective magnetic field region 41 being incident on the incident end (central position) of the irradiation port 100, and adjustment of the charged particle beam in the irradiation port 100 becomes easy. Further, by moving the irradiation port 100 along the shape of the exit side 43 of the effective magnetic field region 41 in the XY plane, the charged particle beam exiting from the effective magnetic field region 41 is easily incident on the incident end of the irradiation port 100, and attenuation of the charged particle beam can be avoided or reduced.

The collector shoe 123 is fixed to the irradiation port 100 via the support member 121, slides along the power supply rail 125 (can move while contacting the power supply rail 125), and supplies power from the power supply rail 125 to the irradiation port 100 or the driving unit 122. The collector shoe 123 can stably receive power supply from the power supply rail 125 regardless of whether the irradiation port 100 is moving or stopping. The electric power supplied from the power supply rail 125 to the collector shoe 123 is used for the operation of the scanning electromagnet 101, the beam monitor 102, and the energy modulation unit 103 of the irradiation port 100, and the operation of the driving unit 122.

Here, as shown in fig. 7, the contact surface 123a of the collector shoe 123 contacting the power feeding rail 125 may be configured to have the same radius of curvature as the power feeding rail 125 on the XY plane (and/or the XZ plane and/or the YZ plane) (in the present invention, "the same" includes a difference of ± 10%), or have an average radius of curvature of the power feeding rail 125. For example, in the case where any portion of the power feeding rail 125 in the driving range of the irradiation port 100 in the XY plane has the same radius of curvature, the contact surface 123a of the collector shoe 123 may be configured to have the same radius of curvature as the radius of curvature of the power feeding rail 125. Even in a place where the contact area between the collector shoe 123 and the power feeding rail 125 is small (for example, a contact point), the contact resistance ratio is large, and heat associated therewith is likely to be generated. However, by configuring the contact surface 123a of the collector shoe 123 to have the same radius of curvature as that of the power supply rail 125, the influence of heat generation due to contact resistance can be eliminated or reduced.

Further, a biasing means (not shown) for applying a constant load to the collector shoe 123 may be provided between the collector shoe 123 and the support member 121. The biasing means may be a member having a double structure of a plate spring and a coil spring, for example, and may apply a predetermined load to the collector shoe 123 sliding on the power supply rail 125 in accordance with the movement of the irradiation port 100. Further, the biasing means for reducing the interference between the power supply rail 125 and the collector shoe 123 may be provided not on the collector shoe 123 but on the power supply rail 125 side (for example, between the insulating member 126 and the fixing member of the end cover 48), and the power supply rail 125 may be biased toward the collector shoe 123 side with a constant load, so that the collector shoe 123 sliding on the power supply rail 125 may be biased with a constant load. Here, the constant load is not limited to the case where the same load is always applied, and means that the load is applied to such an extent that the power supply from the power supply rail 125 to the collector shoe 123 is stably performed.

As shown in fig. 8, the collector shoe 123 may be formed of a plurality of collector portions 123 b. At this time, a biasing unit 123c may be provided between each current collecting portion 123b and the support member 121. Thus, even when the radius of curvature of the power supply rail 125 is not completely uniform within the driving range of the irradiation port 100, the collector shoe 123 can be flexibly and stably brought into contact with the power supply rail 125 so as to follow the shape of the power supply rail 125. Further, it is further preferable that the contact surface of each current collecting portion 123b that contacts the power supply rail 125 has the same radius of curvature as the power supply rail 125 (or the average radius of curvature of the power supply rail 125).

Fig. 9 is a block diagram of the control system 140 for the irradiation port 100, the deflection electromagnet 33, the bunching electromagnet 40, and the power supply system 120.

The control system 140 includes an irradiation control unit 141, an electromagnet control unit 142, a scanning control unit 143, an irradiation port drive control unit 144, and a power supply control unit 145.

The irradiation control unit 141 is a higher-level control unit that monitors a prescribed dose for each target to be irradiated with a charged particle beam, and controls the electromagnet control unit 142, the scanning control unit 143, and the irradiation port drive control unit 144. The electromagnet control unit 142 controls the deflection electromagnet 33 and the beam focusing electromagnet 40 to adjust the deflection angle phi (and the irradiation angle theta) of the charged particle beam. The scan controller 143 sends a command to the power supply controller 145 to control the scanning electromagnet 101 of the irradiation port 100. The irradiation port drive control unit 144 controls the drive unit 122 and transmits a command for controlling the movement of the irradiation port 100 to the power supply control unit 145. The power supply control unit 145 controls power supply to the scanning electromagnet 101 and the driving unit 122 in accordance with commands from the higher-order scanning control unit 143 and the irradiation port drive control unit 144, and operates the scanning electromagnet 101 and the driving unit 122.

The irradiation control unit 141 sends commands to the electromagnet control unit 142 and the irradiation port drive control unit 144 in accordance with a direction (irradiation angle θ) of the charged particle beam to be irradiated to the isocenter O (affected area) set in advance. The electromagnet control unit 142 that receives the command adjusts the current flowing through the deflection electromagnet 33 (and/or the bunching electromagnet 40) so that the irradiation angle θ of the charged particle beam emitted from the bunching electromagnet 40 becomes a predetermined irradiation angle. In addition, the irradiation port drive control unit 144 that has received the command drives the drive unit 122 to move the irradiation port 100 so that the charged particle beam emitted from the bunching electromagnet 40 passes through the entrance end (center) of the irradiation port 100 before the irradiation of the charged particle beam is started.

While the affected part is irradiated with the charged particle beam, the irradiation control unit 141 may receive information (information such as the position, width, and dose of the charged particle beam) from the beam monitor 102 of the irradiation port 100, determine whether or not the irradiation of the affected part with the charged particle beam is appropriate, and perform feedback control. For example, when the direction of the charged particle beam (irradiation angle θ) is inappropriate compared with a direction preset for the affected part based on the information from the beam monitor 102, the electromagnet control unit 142 (and/or the scanning control unit 143) is controlled to finely adjust the irradiation angle θ (and/or fine adjustment is performed by scanning the scanning electromagnet 101 with the charged particle beam within a predetermined range). In addition, when the irradiation amount of the charged particle beam is not appropriate for a value set in advance for the affected part, the irradiation amount of the charged particle beam impinging on the affected part may be adjusted by the energy modulation unit 103 and/or the charged particle beam adjustment unit 31 of the irradiation port 100.

As described above, in the charged particle beam irradiation apparatus 10 of the present embodiment, power is supplied from the power supply rail 125 to the irradiation port 100 without using a relatively thick power supply cable for the irradiation port 100. Therefore, the problem of a large and thick cable housing space with a large bending radius or the problem of damage to the cable due to handling does not occur. Further, since the power feeding rail 125 is provided in the port cover 48, it is not visible from the patient who is receiving the particle beam therapy, and thus it is possible to eliminate or reduce psychological stress and anxiety of the patient. Further, by configuring the shape of the contact surface 123a of the collector shoe 123 to have a radius of curvature that is the same as the radius of curvature of the power supply rail 125 (in the present invention, "the same" also includes a case where the difference is within ± 10%), it is possible to reduce the contact resistance, eliminate or reduce the problem of heat generation, and perform stable power supply. Further, by configuring the collector shoe 123 to include the plurality of collector portions 123b, even when the irradiation port 100 moves, the collector shoe can further follow the shape of the power supply rail 125 and can be continuously in contact with the power supply rail, thereby enabling stable power supply. At this time, a biasing unit 123c may be provided between the collector shoe 123 (or the collector portion 123b) and the support member 121.

The dimensions, materials, shapes, relative positions of the constituent elements, and the like described above are changed according to the structure of the apparatus to which the present invention is applied and various conditions. It is not intended to limit the specific terms and embodiments used in the description to those skilled in the art, and other equivalent components may be used, and other modifications and variations may be made to the above-described embodiments without departing from the spirit or scope of the invention. In addition, features described in connection with one embodiment of the invention may be used with other embodiments, even if not explicitly mentioned.